Generate for-in-range loop as counter loop when possible

If an upper bound is a compile-time constant != Int.MAX_VALUE,
we can generate 'for (i in x..N)' as 'for (i in x until N+1)'.

compiler/backend/src/org/jetbrains/kotlin/codegen/range/PrimitiveNumberRangeLiteralRangeValue.kt

@@ -18,14 +18,33 @@ package org.jetbrains.kotlin.codegen.range
 
 import org.jetbrains.kotlin.codegen.ExpressionCodegen
 import org.jetbrains.kotlin.codegen.range.forLoop.ForInRangeLiteralLoopGenerator
+import org.jetbrains.kotlin.codegen.range.forLoop.ForInUntilConstantRangeLoopGenerator
+import org.jetbrains.kotlin.codegen.range.forLoop.ForLoopGenerator
 import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.psi.KtForExpression
 import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
+import org.jetbrains.kotlin.resolve.constants.*
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
 class PrimitiveNumberRangeLiteralRangeValue(rangeCall: ResolvedCall<out CallableDescriptor>): PrimitiveNumberRangeIntrinsicRangeValue(rangeCall) {
     override fun getBoundedValue(codegen: ExpressionCodegen) =
             SimpleBoundedValue(codegen, rangeCall)
 
-    override fun createForLoopGenerator(codegen: ExpressionCodegen, forExpression: KtForExpression) =
+    override fun createForLoopGenerator(codegen: ExpressionCodegen, forExpression: KtForExpression): ForLoopGenerator =
+            getConstRangeForInRangeLiteralGenerator(codegen, forExpression) ?:
             ForInRangeLiteralLoopGenerator(codegen, forExpression, rangeCall)
+
+    private fun getConstRangeForInRangeLiteralGenerator(codegen: ExpressionCodegen, forExpression: KtForExpression): ForLoopGenerator? {
+        val rhsExpression = rangeCall.valueArgumentsByIndex?.run { get(0).arguments[0].getArgumentExpression() } ?: return null
+        val constValue = codegen.getCompileTimeConstant(rhsExpression).safeAs<IntegerValueConstant<*>>() ?: return null
+        val untilValue = when (constValue) {
+            is ByteValue -> constValue.value + 1
+            is ShortValue -> constValue.value + 1
+            is IntValue -> constValue.value + 1
+            else -> return null
+        }
+        // Watch out for integer overflow
+        if (untilValue == Int.MIN_VALUE) return null
+        return ForInUntilConstantRangeLoopGenerator(codegen, forExpression, rangeCall, untilValue)
+    }
 }

compiler/backend/src/org/jetbrains/kotlin/codegen/range/forLoop/ForInUntilConstantRangeLoopGenerator.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.codegen.range.forLoop
+
+import org.jetbrains.kotlin.codegen.ExpressionCodegen
+import org.jetbrains.kotlin.codegen.StackValue
+import org.jetbrains.kotlin.psi.KtExpression
+import org.jetbrains.kotlin.psi.KtForExpression
+import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
+import org.jetbrains.kotlin.resolve.constants.*
+import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue
+
+class ForInUntilConstantRangeLoopGenerator(
+        codegen: ExpressionCodegen,
+        forExpression: KtForExpression,
+        loopRangeCall: ResolvedCall<*>,
+        private val untilValue: Int
+) : AbstractForInExclusiveRangeLoopGenerator(codegen, forExpression) {
+    private val from: ReceiverValue = loopRangeCall.dispatchReceiver!!
+
+    override fun generateFrom(): StackValue =
+            codegen.generateReceiverValue(from, false)
+
+    override fun generateTo(): StackValue =
+            StackValue.constant(untilValue, asmElementType)
+}

compiler/testData/codegen/box/ranges/forInRangeToConstWithOverflow.kt

@@ -0,0 +1,12 @@
+const val M = Int.MAX_VALUE
+
+fun box(): String {
+    var step = 0
+    for (i in M .. M) {
+        ++step
+        if (step > 1) throw AssertionError("Should be executed once")
+    }
+    if (step != 1) throw AssertionError("Should be executed once")
+
+    return "OK"
+}

compiler/testData/codegen/bytecodeText/forLoop/forInRangeToConst.kt

@@ -0,0 +1,12 @@
+const val N = 42
+
+fun test(): Int {
+    var sum = 0
+    for (i in 1 .. N) {
+        sum += i
+    }
+    return sum
+}
+
+// 0 IF_ICMPEQ
+// 1 IF_ICMPGE

compiler/tests-ir-jvm/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -13322,6 +13322,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             doTest(fileName);
         }
 
+        @TestMetadata("forInRangeToConstWithOverflow.kt")
+        public void testForInRangeToConstWithOverflow() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInRangeToConstWithOverflow.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("forInRangeWithImplicitReceiver.kt")
         public void testForInRangeWithImplicitReceiver() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInRangeWithImplicitReceiver.kt");

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -13322,6 +13322,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
+        @TestMetadata("forInRangeToConstWithOverflow.kt")
+        public void testForInRangeToConstWithOverflow() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInRangeToConstWithOverflow.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("forInRangeWithImplicitReceiver.kt")
         public void testForInRangeWithImplicitReceiver() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInRangeWithImplicitReceiver.kt");

compiler/tests/org/jetbrains/kotlin/codegen/BytecodeTextTestGenerated.java

@@ -1238,6 +1238,12 @@ public class BytecodeTextTestGenerated extends AbstractBytecodeTextTest {
             doTest(fileName);
         }
 
+        @TestMetadata("forInRangeToConst.kt")
+        public void testForInRangeToConst() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/bytecodeText/forLoop/forInRangeToConst.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("forInRangeWithImplicitReceiver.kt")
         public void testForInRangeWithImplicitReceiver() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/bytecodeText/forLoop/forInRangeWithImplicitReceiver.kt");

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -13322,6 +13322,12 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             doTest(fileName);
         }
 
+        @TestMetadata("forInRangeToConstWithOverflow.kt")
+        public void testForInRangeToConstWithOverflow() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInRangeToConstWithOverflow.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("forInRangeWithImplicitReceiver.kt")
         public void testForInRangeWithImplicitReceiver() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInRangeWithImplicitReceiver.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -14942,6 +14942,12 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             doTest(fileName);
         }
 
+        @TestMetadata("forInRangeToConstWithOverflow.kt")
+        public void testForInRangeToConstWithOverflow() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInRangeToConstWithOverflow.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("forInRangeWithImplicitReceiver.kt")
         public void testForInRangeWithImplicitReceiver() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/ranges/forInRangeWithImplicitReceiver.kt");